Human hair undergoes a normal growth cycle where each hair grows continuously for approximately 2 to 4 years, and stops growing for 2 to 4 months, and then falls out. In its place, a new healthy hair begins to grow and this cycle is repeated. The hairs on the head are always in different stages of the cycle, so it is normal to loose scalp hair everyday. On average, up to about 100 hairs is lost per day.
In male pattern hair loss, the normal hair growth cycle is disrupted and more than the average number of hairs are shed per day without having the old hairs replaced by new ones. Male pattern hair loss is determined by a combination of male hormones (androgens) and heredity. Men susceptible to male pattern baldness usually experience the onset sometime in their 20's and it becomes more common as they age. Androgenetic alopecia is the most common type of hair loss in men, with approximately 50% of men experiencing this hair loss to some degree by the age of 50.
In addition to adrogenetic alopecia, other factors may influence hair loss, many of which are temporary. Amongst these factors include stress of an illness or major surgery, medicines, such as those used in chemotherapy, blood thinners, antidepressants, excessive amounts of vitamin A and certain disease states like diabetes.
There is increasing evidence of the link between male pattern hair loss and the level of 5 alpha-reductase. 5 alpha-reductase converts the hormone testosterone into dihydrotestosterone (DHT). There have been many reports of men with male pattern hair loss having increased levels of DHT in the scalp. It appears that DHT contributes to the shortening of the growth phase and thinning of the hair.
A number of preparations have recently been proposed for treating male pattern hair loss, of which the most well known is Minoxidil. Minoxidil is applied topically to the scalp and has been shown to stimulate hair growth in individuals with androgenetic alopecia. The exact mechanism of the action of Minoxidil in the treatment is not know, and it is thought that there is more than one mechanism by which Minoxidil stimulates hair growth. Some of the mechanisms by which Minoxidil may stimulate hair growth include phasodilation of the micro circulation around the hair follicles, which may stimulate hair growth; direct stimulation of the hair follicle cells to enter into a peripheral phase whereby resting phase follicles are stimulated to pass into active phase folicles; or alteration of the effect of androgens on genetically predetermined hair follicles. It was thought that Minoxidil might affect the androgen metabolism in the scalp, inhibiting the capacity of androgens to affect the hair follicles. Another medication utilized for treatment of adrogenetic alopecia is Finisteride. Finisteride is an inhibitor of type II 5-alpha-reductase and has been shown to be effective in decreasing scalp DHT by inhibiting conversion of testosterone to DHT. Oral administration of Finisteride slowed hair loss, increased hair growth and improved the appearance of hair.
5-alpha-reductase enzyme has also been linked to benign prostatic hyperplasia. A number of the medications now utilized for treating the male pattern hair loss were originally developed for treatment of benign prostatic hyperplasia.
Recently, there has been increased interest in the use of natural therapy for treatment of a diseased state. A number of herbal extracts have been demonstrated to be useful in the treatment of benign prostatic hyperplasia. Once such herbal extract is the extract of the berries of Saw Palmetto. Saw Palmetto is a small palm tree with large leaves and large deep red black berries. Saw Palmetto berries contain an oil with a variety of fatty acids and phytosterols. The fat soluble extract of Saw Palmetto berries has been shown to inhibit the conversion of testosterone, which is thought to be responsible for the enlargement of the prostrate. In addition, Saw Palmetto extract inhibits the binding of DHT to receptors, thus blocking DHT's action and promoting the breakdown of the potent compound. Another herbal extract utilized is African Pygeum. Pygeum is a large evergreen tree growing in the higher plateaus of southern Africa. The bark of the tree is processed to produce a fat-soluble fraction, which contains phytosterols, pentacyclic triterpenoids and ferulics esters of long chain fatty acids. African Pygeum extracts in double blind clinical trials have been found to be effective in treating a wide range of prostatic hyperplasia. Consumption of Pygeum extract resulted in a significant amelioration of symptoms, reduction in prostate size and clearance of bladder neck urethral obstruction.
Stinging nettles extract, which are an extract of a perennial plant growing worldwide, have been demonstrated to show a reduction in prostatic growth potential in mice with the administration of a high dosage of the nettle root extract. Stinging nettles have also been traditionally been known as a hair and skin tonic, stimulating hair growth, improving condition of the hair and skin and treating dandruff.
There still remains a need for a natural hair growth stimulant for use in treating androgenetic alopecia, having reduced side effects and risk of toxicity compared with synthesized pharmaceutical compounds.